1 NOPSEMA briefing and MODU mooring systems in cyclonic conditions Kerry Gordon Manager – Assessment & Inspection 10 Sept 2015
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NOPSEMA briefing and
MODU mooring systems in cyclonic conditions
Kerry Gordon
Manager – Assessment & Inspection 10 Sept 2015
Presenter
Presentation Notes
Good morning and thanks to Drillsafe for the opportunity to present Brief update on a selected few topical issues before focusing on MODU mooring; no statistical charts – no new message since my presentation in March here at DrillSafe.
Selected topical issues
• Triennial independent review of NOPSEMA – Stakeholder engagement continues to be a focus
• Legislative change – Amended Wells Regulations commence 1 Jan 2016
• NOPSEMA focused topic inspection program
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Presenter
Presentation Notes
Triennial independent review of NOPSEMA : 1) Independent panel, appointed by Minister, chaired by well respected industry figure Ken Fitzpatrick, sought views of a wide range of stakeholders. 2) Has been completed - Report scheduled to be tabled before parliament later this month and publicly available thereafter. 3) NOPSEMA Stakeholder engagement continues to be a focus, particularly with respect to Environment Plans Amended Wells Regulations – There has been considerable consultation between the Department of Industry and APPEA, IADC and others; so these regs should not be a surprise to anyone. However, NOPSEMA will develop guidance for these regs.
Focus topics 2015
Maintenance management • management of deferral of work • equipment strategies - inspection and monitoring • structural integrity - inspection and monitoring • safety-critical equipment meeting performance standards.
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Presenter
Presentation Notes
Maintenance Management: Evergreen topic – based on root causes for accidents & DO’s Given the recent economic climate and the potential for operators to explore options to cut costs, maintenance management is one area that operators could look for cost-cutting opportunities particularly in relation to marginal developments or facilities reaching the end of field life.
Focus topics 2015
Contractor management • Contractor agreements and performance governance by the
operator in relation to: – how the operator of a diving project effectively ensures
diving contractors are complying with their DSMS/DPP – third party contractors & equipment management – asset integrity monitoring programs conducted by third
parties. • Contractor selection and competency • Operator and contractor interface management e.g. SIMOPS.
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Presenter
Presentation Notes
Operators of facilities who engage contractors must have arrangements in place to ensure that those contractors are appropriately managed to reduce the risks
Focus topics 2015
Blowout source control contingency planning • Currently the degree of contingency planning for a well
blowout (relief well, cap and contain etc) varies between titleholders. NOPSEMA will inspect titleholders arrangements for compliance with the legislation. – Note: new well regulation RMAR Part 5, Reg. 5.09(k) now specifically
addresses the matter.
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Focus topics 2015
Position keeping systems • Stability management including Ballast & Bilge Systems. • Dynamic positioning systems • Pre-lay mooring design • Inspection testing and maintenance including software
updates • Integrity of safety critical elements • Competence (operators and maintainers of position keeping
systems).
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Presenter
Presentation Notes
Recent mooring incidents, an increase in the use of pre-lay systems and the safety-critical importance of Mooring and DP Systems in preventing a Major Accident Event underlines the focus on “Position Keeping Systems”.
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MODU mooring systems in
cyclonic conditions
Background
• The Atwood Osprey experienced a mooring failure during cyclone Olwyn and was blown some three nautical miles off location in the vicinity of subsea and surface infrastructure and environmentally sensitive shorelines
• Investigations have been conducted by NOPSEMA and Atwood who have both committed to sharing lessons learned from this incident with industry.
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Presenter
Presentation Notes
I think everyone in this room understands the potential of this incident and recognizes the potential impact on the industry ‘social licence to operate’ Montebello & Barrow islands 2 independent investigations
Sequence of events - Cyclone Olwyn
• 9 March – Commence well suspension in preparation for rig evacuation
• 10-11 March – Osprey completes well suspension, power- down and evacuation • 12 March – TC Olwyn strikes Atwood Osprey
• 12-13 March – AHTSV reports rig off location ~3nm
13-man team arrives on board to take the rig in tow by the AHTSV and holds station; team departs rig
• 14 March - Commence ROV operations to assess seabed and condition of infrastructure.
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Regulatory perspective
Four known Incidents of MODU loss of position due to Cyclone activity
• Mar 2004 – MODU dragged anchors Cat-3
• Dec 2008 – MODU dragged anchors Cat -2
• Feb 2011 – MODU dragged anchors Cat -3
• Mar 2015 – MODU snapped anchor wire Cat -3
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Regulatory perspective
Six documented instances where MODUs have failed to down-man in the face of impending cyclones.
• Semi-Sub MODU 2004
• Jack-Up MODU 2006
• Semi-Sub MODU 2007
• Semi-Sub MODU 2009
• Semi-Sub MODU 2011
• Semi-Sub MODU 2015
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Regulatory perspective continued
Inconsistency in safety case design and performance standards utilised in mooring design and analysis.
• “50 year return period” - 1 case
• “API RP 2SK using 20 year return period” - 2 cases
• “API RP 2SK using 10 year return period” - 1 case
• “specification to ABS rules and MODU code” - 1 case
• completely silent on design and performance standards for mooring systems. - 3 cases
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Presenter
Presentation Notes
Current practice indicates there is a range of standards being applied – but arguably weighted towards the lowest common denominator. We need to move the bar up in terms of industry practice here. Better practice is being applied elsewhere.
Investigation overview
• Hind-cast computer modelling
• ROV survey of the seabed
• Review of the mooring system design and its component parts
• Inspection of critical components
• Visual inspection, metallurgical analysis and destruction testing of the mooring lines
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Presenter
Presentation Notes
plausible order in which the mooring lines parted Survey to confirm the final positions of the mooring lines and anchors to help confirm the hindcast modeling. In summary, this analysis concludes material weaknesses in component parts of the mooring system, (caused in part by the system’s pre-laid design and in part by loss of strength in the rig’s wire ropes and prelaid fibre rope)
Investigation overview continued
• Design including pre-laid systems
• Assurance, installation and managing change
• Inspection and maintenance.
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Presenter
Presentation Notes
NOPSEMA Investigation Included consideration of the operator investigation 3 significant areas are identified: 1/ Reliability of the system in foreseeable cyclone conditions. 2/ Interface between facility operator, Title Holder and sub contractors. 3/ Inspection and Maintenance to ensure SCE reliability.
Findings - Mooring design
• Return period (20,50,100 year RP environmental conditions)
• Component positioning
• Lack of detailed risk assessment at the mooring design stage involving all parties
• Deficiencies in the assurance processes at the interfaces between the responsible parties.
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Presenter
Presentation Notes
Higher return period was not used Component positioning: critical mooring components may have been degraded by cyclic contact with the sea floor over time Risk factors: asymmetric mooring pattern -pre laid - fibre rope sections No operator design review for completeness of the location specific mooring design
Mooring installation - Interface
Combination of rig and pre-laid mooring components • Pre lay mooring installation procedures
• Drag anchor pull test tensions
• Management of change.
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Presenter
Presentation Notes
What this is about is the responsibility and communication between Rig operator, Title Holder and subcontractor. Good procedures – potential for component damage during installation or recovery Lower drag anchor pull test tensions were achieved for the sand/silt seabed conditions. Anchor handling vessel winch issues when winch tensions exceeded 200t due to sea swells Management of Change – risk assessment of the deviations made during the pre lay installation activities
Operations, inspection and maintenance
• Records of inspection history
• Frequency of inspections
• Competency assurance system for mooring equipment/rope inspectors
• Lack of performance standards and the necessary associated assurance tasks for the mooring system – ongoing availability and reliability of the SCE
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Presenter
Presentation Notes
Fibre ropes used in the make up of 8 out of the 12 mooring legs Inspection reports were dated between 2008-2012 with incomplete records of inspection history, time in service and maintenance Frequency of fibre rope inspections were not linked to age and usage history Rig wire rope inspections not completed per the minimum operating standards Rig fairlead inspections not defined
Recovery preparedness
Opportunities for improvement
• Procedures for managing mooring line tensions for survival conditions/MODU cyclone evacuation
• MODU real time position indication - GPS
• Mooring line tension/weather recording and UPS
• MODU recovery – preparedness for towing
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Presenter
Presentation Notes
Preparations including changes to mooring tensions should be defined and verified. Should be as per the mooring analysis vs. generic 4% slacking off Generally, power generation is shut down and the MODU fully evacuated in response to a confirmed cyclone threat. The inability to identify a loss of rig position in a timely manner may exacerbate the risk of a collision MODU was in proximity to pressurized pipe line required manning to be able to connect tow – personnel exposed to risk
Key learnings - Mooring failure
• Reliability of the mooring system under foreseeable cyclone conditions
• Assurance of mooring design, installation and critical component materials – quality control
• The interface: SCE - inspection, maintenance, MoC and operations procedures
• Recovery preparedness and. response
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Presenter
Presentation Notes
Increased safety factors are necessary for higher consequences of a loss of position. Poor quality control – mooring components unable to withstand their full design load. Interface between MODU operators, titleholders and service providers needs to be well managed. Simple mitigation controls like GPS, Tension/weather monitoring/ emergency tow.
Regulatory approach and expectations
MODU mooring workshop
Provided an opportunity for industry and NOPSEMA to collectively examine better ways to manage this significant risk. • Provide information about the incident and lessons learned • Communicate regulatory requirements and perspective • Discuss opportunities for improvement
– identify any actions on which immediate consensus can be reached
– identify areas for which there is consensus in direction but require more work to define detail.
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Workshop inputs
• NOPSEMA and Atwood investigation findings • Information paper provided for context • Consideration of existing standards and practices
from elsewhere
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Regulatory expectations
To strengthen requirements with a view to improving the situation: • Achieve consensus on what is best practice in relation to
each of these issues; • Determine current industry knowledge and approach with
respect to mooring design criteria; • Assess and manage the risks arising from these issues with
respect to the impending cyclone season and longer term.
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Presenter
Presentation Notes
NOPSEMA does not have a pre-determined position or outcome but does hold the view that improvement in managing these risk is practicable – aiming to gauge industry perspective and determine if there is a consensus view on what is best practice (Not contemplating initiating legislative change)
Regulatory expectations
Safety case considerations:
• rig operators - mooring systems are safety critical
Current considerations:
• understand the design basis and integrity of current hardware
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Presenter
Presentation Notes
consideration of performance standards to satisfy ALARP criteria – can they be met? Including inspection pre-lays considering time in situ and verify pull-tests before hook-up, etc, Heads up: Overall consideration of these matters may lead to a review of technical and other risk controls and a possible need for safety case revisions.
Next steps
NOPSEMA will issue regulatory guidance: • to address key issues identified and recognized in the
workshop and in the information paper;
• to raise awareness and prompt a review of arrangements in place for the immediately forthcoming cyclone season; and
• to provide guidance on key interface points between titleholders and operators which should be addressed in the rig safety case
Methodology for topics requiring further work
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Thankyou
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